From b01a85dfd5e8cda7170b7ba6fe66fc3800f93990 Mon Sep 17 00:00:00 2001
From: Alexandros Frantzis <alexandros.frantzis@collabora.com>
Date: Tue, 28 Feb 2023 23:42:59 +0200
Subject: [PATCH] client: Do not warn about attached proxies on default queue
 destruction.

If the default queue is being destroyed, the client is disconnecting
from the wl_display, so there is no possibility of subsequent events
being queued to the destroyed default queue, which is what this warning
is about.

Note that interacting with (e.g., destroying) a wl_proxy after its
wl_display is destroyed is a certain memory error, and this warning will
indirectly warn about this issue. However, this memory error should be
detected and warned about through a more deliberate mechanism.

Signed-off-by: Alexandros Frantzis <alexandros.frantzis@collabora.com>
---
 src/wayland-client.c | 14 ++++++----
 tests/queue-test.c   | 63 +++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 71 insertions(+), 6 deletions(-)

diff --git a/src/wayland-client.c b/src/wayland-client.c
index a50fc18..054c0c7 100644
--- a/src/wayland-client.c
+++ b/src/wayland-client.c
@@ -304,14 +304,18 @@ wl_event_queue_release(struct wl_event_queue *queue)
 	if (!wl_list_empty(&queue->proxy_list)) {
 		struct wl_proxy *proxy, *tmp;
 
-		wl_log("warning: queue %p destroyed while proxies still "
-		       "attached:\n", queue);
+		if (queue != &queue->display->default_queue) {
+			wl_log("warning: queue %p destroyed while proxies "
+			       "still attached:\n", queue);
+		}
 
 		wl_list_for_each_safe(proxy, tmp, &queue->proxy_list,
 				      queue_link) {
-			wl_log("  %s@%u still attached\n",
-			       proxy->object.interface->name,
-			       proxy->object.id);
+			if (queue != &queue->display->default_queue) {
+				wl_log("  %s@%u still attached\n",
+				       proxy->object.interface->name,
+				       proxy->object.id);
+			}
 			proxy->queue = NULL;
 			wl_list_remove(&proxy->queue_link);
 			wl_list_init(&proxy->queue_link);
diff --git a/tests/queue-test.c b/tests/queue-test.c
index 63abc19..4129310 100644
--- a/tests/queue-test.c
+++ b/tests/queue-test.c
@@ -308,12 +308,22 @@ client_test_queue_set_queue_race(void)
 }
 
 static char *
-map_file(int fd, size_t *len)
+maybe_map_file(int fd, size_t *len)
 {
 	char *data;
 
 	*len = lseek(fd, 0, SEEK_END);
 	data = mmap(0, *len, PROT_READ, MAP_PRIVATE, fd, 0);
+
+	return data;
+}
+
+static char *
+map_file(int fd, size_t *len)
+{
+	char *data;
+
+	data = maybe_map_file(fd, len);
 	assert(data != MAP_FAILED && "Failed to mmap file");
 
 	return data;
@@ -422,6 +432,45 @@ client_test_queue_proxy_event_to_destroyed_queue(void)
 	wl_display_disconnect(display);
 }
 
+static void
+client_test_queue_destroy_default_with_attached_proxies(void)
+{
+	struct wl_display *display;
+	struct wl_callback *callback;
+	char *log;
+	size_t log_len;
+	char callback_name[24];
+	int ret;
+
+	display = wl_display_connect(NULL);
+	assert(display);
+
+	/* Create a sync dispatching events on the default queue. */
+	callback = wl_display_sync(display);
+	assert(callback != NULL);
+
+	/* Destroy the default queue (by disconnecting) before the attached
+	 * object. */
+	wl_display_disconnect(display);
+
+	/* Check that the log does not contain any warning about the attached
+	 * wl_callback proxy. */
+	log = maybe_map_file(client_log_fd, &log_len);
+	ret = snprintf(callback_name, sizeof(callback_name), "wl_callback@%u",
+		       wl_proxy_get_id((struct wl_proxy *) callback));
+	assert(ret > 0 && ret < (int)sizeof(callback_name) &&
+	       "callback name creation failed (possibly truncated)");
+	assert(log == MAP_FAILED || strstr(log, callback_name) == NULL);
+	if (log != MAP_FAILED)
+		munmap(log, log_len);
+
+	/* HACK: Directly free the memory of the wl_callback proxy to appease
+	 * ASan. We would normally use wl_callback_destroy(), but since we have
+	 * destroyed the associated wl_display, using this function would lead
+	 * to memory errors. */
+	free(callback);
+}
+
 static void
 dummy_bind(struct wl_client *client,
 	   void *data, uint32_t version, uint32_t id)
@@ -536,3 +585,15 @@ TEST(queue_proxy_event_to_destroyed_queue)
 	/* Check that the client aborted. */
 	display_destroy_expect_signal(d, SIGABRT);
 }
+
+TEST(queue_destroy_default_with_attached_proxies)
+{
+	struct display *d = display_create();
+
+	test_set_timeout(2);
+
+	client_create_noarg(d, client_test_queue_destroy_default_with_attached_proxies);
+	display_run(d);
+
+	display_destroy(d);
+}